Electromagnetic switch for electric service lines



July 21, 1936. J. E. FARRELL ELECTROMAGNETIC SWITCH FOR ELECTRIC SERVICE LINES Filed Feb. 5,A 1955 2 Sheets-Sheet 1 17W E19-- (wpfu B B V HMH E "I V m E 2f Z5 n 15 5 @L 3 f" ./7 f 5 ,e lrlg. Z5

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July 21, 1936. J. E. FARRELL 2,048,250

ELECTROMAGNETIC SWITCH FOR ELECTRIC SERVICE LINES Filed Feb 5, 1955 2 Sheets-Sheet 2 ZZ I JosphE arma,

Patented July 21, 1936 UNITED STATES PATENT QFFICE ELECTROMAGNETIC SWITCH FOR ELECTRIC SERVICE LINES Application February 5, 1935, Serial No. 5,139

7 Claims.

This invention relates to an electro-magnetic service line protecting device of the type which automatically functions upon the existence of an undesirable condition in the line, and which may be manually reset when normal line conditions are restored without removing the device from its service position.

One of the objects of the invention is to provide a simple and practical arrangement of parts which lend themselves readily to manufacturing practice and expediency, thereby facilitating assembly and lowering production costs, while at the same time maintaining a high standard of effectiveness and insuring the reliability of the device under all conditions of use.

A further object of the invention is to provide a device of the plug type having a surmounting switch housing and which readily adapts itself to use in a standard fuse receptacle box in the frespect that the dimensions of the device along its vertical axis and diameter not only permit of the same being readily inserted in the line sockets of the receptacle without interfering with one another, but at the same time permit the cover of the box to be readily closed in the usual manner.

With the above and other objects in view which will more readily appear as the nature of the invention is better understood, the same consists in the novel features of construction, combination and arrangement of parts as will be hereinafter more fully described, illustrated in the accompanying drawings and dened in the appended claims.

A preferred and practical embodiment of the invention is shown in the accompanying drawings, in which:-

Figure 1 is a side elevation of the improved device.

Figure 2 is a top plan view thereof.

Figure 3 is a vertical sectional view taken on the line 3--3 of Figure 2 and showingfthe switch parts in their normal position.

Figure 4 is a top plan -view of the switch block or boss and associated parts, the resetting member and cover being removed to expose the same.

Figure 5 is a detail vertical sectional view similar to Figure 3, showing the. relative position of parts when the switch has been opened, and the short or overload persists in the line.

Figure 6 is a vertical sectional view taken on the line 6-6 of Figure 5, showing one side of the switch block.

Figure '7 is a vertical sectional view of a receptacle including a plurality of the present devices.

Figure 8 is a plan view of the receptacle shown in Figure 7 with the cover open.

Figure 9 is a horizontal sectional view taken on the line 9-9=of Figure 5.

Figure l0 is a bottom plan view of the reset- 5 ting member. l

Figure 11 is a perspective view of the pivoted switch member.

Figure 12 is a perspective view of the bracket which supports the pivoted switch member of Figure 11.

Figure 13 is a perspective view of the insulation member or barrier and the armature type latch.

Similar reference characters designate corre- 15 sponding parts throughout the several figures o! the drawings.

Referring to the drawings, it may be pointed out that the present invention includes in its organization a plug A, a cover B, an interior 2O switch boss or block C and a resetting member D. The part C may be made as a block separate from the plug or it may be made integral with the plug as shown. In either case it serves to directly house the major part of the movable switch contact and to slidably support the switch control elements.

The plug A includes a base I having external line terminals in the form of a center contact 2 and a screw shell 3, and houses within thesame an electro-magnet M consisting of a winding and a core. The core forms a part of the line terminal 2 and the head 4 of the core is exposed at the inner face of the plug base. The winding of the magnet has one end connected to the core as at while the other end y leads to a fixed switch contact 5 also at the inner face of the plug base.

The switch block C is of insulating material and is provided with a central passageway having lower and upper guideways 6 and 1. The central passage of the switch block houses a pivoted switch member 8 in the form of a movable frame having a contact 9 at one end, for engaging with the fixed contact 5, while' its opposite end is pro- 45 vided with the laterally disposed pintle portions IIJ for engaging in the openings II of a metallic yoke I2 having a pendant portion I3 which directly contacts with the screw shell 3. The arrangement described provides iixed and movable contacts which are normally closed to maintain the circuit between the terminals 2 and 3. The frame 8 is also provided with an oii'set or angular portion 8a having an opening 8b for receiving at its inner side one end of a spring I4. This spring n engages the part 8El below the pintles I0, thereby normally to force the contact 9 toward the fixed. contact 5 on the inner surface of the plug base. The lower guideway 6 of the insulation block C cooperates with the inner surface of the plug base I to slidably guide an insulation barrier I5 therein. Although the side edges of the insulation member are shown to be of dove-tailed formation to mate with the lower guideway 6, it will be understood that they may be of any other design suitable for the purpose.

The toe portion I6 of the insulation member I5 is preferably bevelled to facilitate the entry of the insulation member or barrier between the contacts 5 and 8 automatically upon demand. The heel of the insulation member I5 is preferably provided with the'upstanding members I1 which pivotally receive therebetween a metallic latch I8. This latch is provided on its under side with a socket for housing a spring I9 which normally urges the latch away from the insulation member. The insulation member I5 overlies the head 4 of the magnet and is urged in one direction by the spring I9 whose free end fits in the socket 2| (Figure 13) of the insulation member. It will also be apparent from the foregoing description that the metallic latch I8 lies between the arms of the frame 8 and, therefore, the latch is free to operate in conjunction with the resetting member D which is confined between the switch block and the inside of the cover.

The resetting member D preferably includes a body portion 2| Whose side edges 22 slidably engage in the upper guideway 1 of the switch block. The upper face of the body 2| is provided with an operators projection 23 which moves in a slot 24 in the cover B. The vunder side of the body 2| is provided with a shoulder 25 adapted to be engaged normally by the latch I8 as shown in Figure 3. Moreover, the underside of the body 2| carries a spring detent 26 intended to engage with an abutment 21 formed by a notch or depression in the bottom wall of the upper guide- Way 'I of the switch block. Also, the body of the ilesetting member D is urged forwardly by spring When the parts are in their assembled relation as shown in Figures 3 and 5 for example, the device is ready for use in the socket of a fuse receptacle. Normally, the contacts 5 and 9 (Figure 3) are engaged to maintain the circuit in a line including, the center contact 2 of the plug; the winding of the electro-magnet M and -fixed contact 5; screw shell 3; bracket |2-|3; frame 8 and pivoted contact 9.

When an overload or siirt occurs in the line, the magnet M is energized. When this occurs, the metallic latch I8 is drawn downwardly compressing the spring I9 and disengaging the shoulder 25 of the resetting member. Since the latch I8 is carried by the insulation member I5 ywhich is urged by spring I9, it will be apparent that as soon as the latch is released from the shoulder 25, the insulation member I5 will be thrust forward to separate the contacts. In so doing, it will also be apparent that the latch I8 is drawn below the plane of the detent 26 on the resetting member which engages the abutment 21. Since the nose of the member I8 may be beveled and its upper surface will be inclined downwardly when the latch is attracted by the head of the electromagnet, the forward thrust of insulation member I5 and latch I8 will cam or lift the detent 26 out of engagement with the abutment 21 and release the resetting member D so that its spring I8* will thrust the resetting member forward.

Assuming that the undesirable condition in the line is only temporary and its cause is remedied or quickly repaired, the latch I8 will be released so that the spring I8 will push the latch upwardly and into the path of the shoulder 25 of the resetting member. The said resetting member may then be moved backwardly and pull or drag the latch and the insulation member I5 backwardly to their normal positions. Also, the spring detent 26 will again snap down into the notch and engage with the abutment 21 to maintain the resetting member D in its normal position. The circuit will then be restored through the fixed contact 5 and movable contact 8.

However, on the other hand, if the short or l.overload is of such character that it might tend to persist or recur, no damage to the line can result because the contacts 5 and 8 are separated by the insulated barrier I5-I6 and no burning or arcing can occur because the circuit is positively broken and the contacts of the automatic device are fully insulated from each other. If it should be attempted to manually reset the switch while the short in the line continues, it will be impossible to do so, because, as soon as the resetting member is moved slightly toward its normal position, it will also carry the latch I8 and insulating member I5 with it. As soon as the contact 9 slides down the bevelled toe I6 of the barrier I5 it will again temporarily engage the contact 5. If the short or overload continues, the magnet will again function to pull the latch I8 down and, therefore, out of engagement with the shoulder 25 which will immediately free up the resetting member and cause the insulation barrier to be thrust back between the contacts 5 and 9. As long as the undesirable condition in the line continues, each attempt to reset the switch will'be defeated, because as soon as the contacts 5 and 8 engage, the magnet circuit will be completed and the amature type latch I8 will be pulled downwardly.

Referring to Figures 7 and 8 it will be observed that there is shown a fuse receptacle support or box 30 having a cover 3| and intended to receive and house a plurality of receptacles 32 which ordinarily receive fuse plugs, but which in the present instance receive automatic line protectl,

ing devices of the type shown and described herein. As will be observed from the drawings, the vertical and lateral dimensions of the device according to the present invention are such that they may be fitted in a receptacle having sockets l spaced in accordance with standard specifications. In other words, devices according to the present invention may be used in standard equipment without change in the latter and without interfering with each other or preventing the closing of the cover or door for the receptacle. To state the matter another way, the housings surmounting the plugs which are fitted into the receptacles are of a diameter whose radius is less than half the distance between the axis of any two given receptacles. Also, the heighth of each device along its vertical axis is less than the depth of the receptacle when the devices are fitted in the receptacle sockets, thereby providing ample clearance to permit of the receptacle door or cover 3| being closed in the usual manner.

I claim:-

l. An electrical service line protecting device comprising an electro-magnet adapted to be energized when an overload occurs in the line, ay

fixed contact, a pivoted contact including an open frame part having an ofset portion disposed radial to its pivot axis, a spring engaging said offset portion for normally urging the pivoted contact toward the fixed contact, a shiftable insulation member arranged within said frame, and overlying the electro-magnet and adapted to be thrust between said contacts, a spring actuated resetting member having a shoulder, means for holding said resetting member in restrained position, and spring urged latch means carried by the insulating' member for normally engaging the shoulder4 on the resetting member to thereby hold the insulation member in normal position, said latch means being responsive to the electro-magnet for releasing the insulation member to separate the contacts.

2. An electrical service line protecting device including an electro-magnet adapted to be energized when an overload occurs in the line, a fixed contact, a pivoted contact, a spring for normally urging the pivoted contact toward the fixed contact, a shiftable insulation member overlying the electro-magnet and adapted to be thrust between said contacts, spring latch means carried by th'e insulation member, a resetting member overlying the insulation member and having a shoulder adapted to be engaged by said latch and means for automatically locking and holding the resetting member in normal position, a part of said means lying in the path of movement of the latch and adapted to be engaged andmoved by said latch when the same is released to free the resetting member.

3. An electrical service line-protecting device including a body and a plug portion, an electromagnet in said plug portion and adapted to be energized when an overload occurs in the line, fixed and pivoted contacts in the body, a spring for normally urging the pivoted contact to the fixed contact, a shiftable insulation member overlying the electro-magnet and adapted to be thrust between said contacts, spring latch means carried by the insulation member, a resetting member overlying the shiftable insulation member and having a shoulder adapted to be engaged by said latch, and a spring detent carried by the resetting member for engaging in a notch in the body to hold the resetting memberl in normal position, said detent lying in the path of movement of the latch carried by the shiftable insulation member Y and adapted to be lifted by said latch when the insulation member is released to thereby free the resetting member.

4. An electrical service line protecting device including a plug having an-electro-magnet therein and adapted to be energized when an overload occurs in the line, an insulation switch block having an abutment, a housing provided with an opening covering said switch base, a xed contact, a pivoted contact operating within a passage in said block, a spring for normally urging the pivoted contact to the fixed contact, a shiftable insulation member slidably guided in the block and overlying the electro-magnet, a spring for tensioning said insulation member, latch means carried by the insulation member and urged in one direction by a spring, a resetting member slidable between the switch base and said housing and having an operating member projecting through the opening therein, a shoulder on the resetting member adapted to be engaged by said latch, a spring detent on the resetting member adapted to normally engage in said abutment of the switch base, and a spring for tensioning the resetting member.

5. An electrical service line protecting device including a plug base, an electro-magnet in the base and adapted to be energized when an overload occurs in the line, a switch block mounted on the plug, an abutment on the block, a housing having an opening and mounted on the plug base to cover the switch block, a fixed contact on the plug base, a pivoted contact mounted on a yoke carried by the plug base, a spring for normally urging the pivoted contact toward the fixed contact, an insulation member slidably guided in the switch block and overlying the electro-magnet in the plug, a spring tending to thrust the insulation member between the iixed and pivoted contacts, a latch carried by the insulation member, a spring for urging the latch away from the insulation member, a spring tensioned resetting member slidably mounted between the switch base and the housing and having a portion projecting through the opening therein, ashoulder on the resetting member adapted to be engaged by said latch, a spring detent carried by the resetting member and normally engaging in said abutment on the base and adapted to be moved away from the abutment by the latch when the latter is attracted by the electro-magnet and released from said shoulder. l

6. An electrical service line protecting device including a plug base having line terminals, an electro-magnet in circuit with one of said terminals, a fixed contact on the base in circuit with the Winding of the electro-magnet, a switch block, a pivoted contact mounted on the plug base and in circuit with one of the line terminals, spring means for normally urging the pivoted contact toward the fixed contact, abutment means on the switch block, a cover adapted to be mounted on the plug base to house the switch block and having an opening, a manually manipulated member slidably arranged between the switch block and the cover and having a portion projecting through the opening therein, a shoulder on said member, spring means for tensioning said member, a spring detent carried vby said member and4 adapted to engage with said abut-1 ment means on said switch base to hold said member in normal position, an insulation member slidably mounted in the switch block, spring means for urging said member in a direction to separate the'pivoted and fixed contacts, an armature type latch carried by the insulation member, and a spring between the insulation member and the latch for urging the latch toward the shoulder of the said manually manipulated member under normal conditions.

7. In an electrical service line protecting device, a plug base, a fixed contact thereon, an insulating switch block having a passageway provided with upper and lower guideways next to said base, a cover detachablyfitted to the baser to house the block and having an opening, a resetting member slidably mounted in the upper guideway of the base and having a portion projecting through the opening in the cover, a shoulder on the under side of the resetting member, a spring for tensioning said resetting member, an abutment on the switch block, a spring detent on the resetting member adapted to engage with said abutment, a fixed contact on the base, a pivoted Contact mounted on the base and lying in the passageway of the block, a spring for normally urging said pivoted contact towards the on the under side of the insulation member, and said latch being subject to the inuence of the electro-magnet to compress the spring confined therebetween and the insulation member to withdraw said latch from engagement with the shoulder on the resetting member.

JOSEPH E. FARREIL. 

